We have been developing an analytical scheme to identify cytokines present in tears. This is a challenging task, since cytokines are thought to be present in tears at very low levels, perhaps as little as a few femtomoles per microliter, while a number of other proteins are known to be much more prevalent in tears (> 10 picomoles per microliter). We have focused on developing matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometric techniques to satisfy the level of sensitivity required to identify cytokines. We have developed techniques that permit us to detect as little as a few hundred attomoles of a cytokine in a model solution. Our goal is to attain the class selectivity required for this project.